Therapeutic impacts of vaccines can be compromised by many challenges. One challenge is the delivery of a vaccine to a subject. For example, multiple administrations are often required to provide successful immunity, which can decrease the likelihood that a subject will take the necessary steps to obtain a required second or more administrations. In addition, vaccines and vaccine formulations often exhibit increased instability during storage, transport and handling, and the vaccine supply chain can require expensive and logistically complex refrigeration (e.g., cold chain requirements). Further, certain vaccines against a particular pathogen must be separately administered at the same time or at different times to a subject to avoid being ineffective when combined or administered at the same time as another vaccine against another pathogen. Additionally, vaccines and vaccine formulations are typically associated with high manufacturing costs, which can limit their availability to those in need.